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EVIDENCE FOR TWO DIFFERENT Na+-DEPENDENT [3H]-OUABAIN BINDING SITES OF A Na+-K+-ATPASE OF GUINEA-PIG HEARTS
| Content Provider | Scilit |
|---|---|
| Author | Fricke, U. Klaus, W. |
| Copyright Year | 1977 |
| Description | Journal: British Journal of Pharmacology 1 The influence of various $Na^{+}$ concentrations on $[^{3}$H]-ouabain binding was studied in experiments on a microsomal $Na^{+}-K^{+}$-adenosine triphosphatase (ATPase) from guinea-pig hearts. 2 The ATP-independent cardiac glycoside binding was not influenced by increasing $Na^{+}$ concentrations. However, a good correlation was found between the ATP-dependent $[^{3}$H]-ouabain binding and $Na^{+}$ concentration. 3 A more detailed analysis of these results according to Hofstee (1952) revealed two distinct processes involved in this interaction: one ouabain binding process was activated at rather low $Na^{+}$ concentrations, $(K_{0.5}$ = 4.5 mM); this type of $[^{3}$H]-ouabain binding was strongly correlated to the $Na^{+}$ concentration necessary for half maximum phosphorylation $(K_{0.5}$ = 1 mM). The other ouabain binding process was predominant at high $Na^{+}$ concentrations $(K_{0.5}$ = 69 mM). 4 On the basis of the commonly accepted ATPase reaction cycle a model for the interaction of cardiac glycosides with the $Na^{+}-K^{+}$-ATPase is proposed, assuming two different binding sites for cardiac glycosides $(E_{2}$-P and $E_{1}$-P) and involving a translocation of these drugs from an outer to an inner compartment of the cell membrane. |
| Related Links | http://europepmc.org/articles/pmc1667879?pdf=render https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1667879/pdf https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1476-5381.1977.tb08435.x |
| Ending Page | 428 |
| Page Count | 6 |
| Starting Page | 423 |
| e-ISSN | 14765381 |
| DOI | 10.1111/j.1476-5381.1977.tb08435.x |
| Journal | British Journal of Pharmacology |
| Issue Number | 3 |
| Volume Number | 61 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 1977-11-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: British Journal of Pharmacology Peripheral Vascular Disease Ouabain Binding Cardiac Glycosides |
| Content Type | Text |
| Resource Type | Article |
